During an earnings conference call earlier this week, Qualcomm announced that it had begun sampling MDM9x25 to customers. MDM9x25 is Qualcomm's its third generation multimode 28nm baseband, the successor to MDM9x15, and also is Qualcomm's first UE Category 4 LTE baseband with 3GPP Release 10 support. Previous LTE basebands MDM9x00 (45nm) and MDM9x15 (28nm) were UE Category 3, which means a maximum of 100 Mbps of throughput on the downlink, even on 20 MHz wide LTE channels. Category 4 LTE modems will be able to use the full 100 resource blocks on 20 MHz FDD-LTE and thus see up to 150 Mbps of throughput, you just need a carrier that has 20 MHz FDD-LTE rolled out. In addition MDM9x25 will include support for LTE carrier aggregation inter-band and intra-band to aggregate together enough spectrum to get effectively 20MHz .

In addition, MDM9x25's support for 3GPP Release 10 means inclusion of inter-band and intra-band carrier aggregation for WCDMA, in addition to MIMO support on top of DC-HSPA+. This means a theoretical bitrate of 84 Mbps for the carrier aggregation plus MIMO modes on WCDMA.

We have a lot more information about MDM9x25 and the current state of Qualcomm's upcoming modem and transceiver portfolio that we'll be going over in a larger piece in the coming week. Expect to see devices based on MDM9x25 start shipping sometime in 2013.

But in that case, the chip is able to aggregate 2x 20 as well, if there was such network, isn't it? If so, it is quite odd that neither Qualcomm nor you in this article emphasize it could do even 300 Mbps.

Also I've just noted: "inter-band and intra-band carrier aggregation for WCDMA, in addition to (..) DC-HSPA+." Wait. DC-HSPA+ is carrier aggregation already, what's the addition?Reply

Not necessarily. If they don't have enough calculation ability on board to perform the 2x as many FFTs required for 2x20MHz throughput, not to mention also calculating the FEC, then they can't do it.

And I would imagine that by now Qualcomm are very good at including on their chips precisely as much calculation as is needed for a particular target throughput and nothing more --- no point in wasting die and power on ability that is never used.Reply

Release 8 W-CDMA supports HSPA+ as dual carrier or MIMO but not both. Furthermore, it supports DC-HSPA+ but only with directly adjacent dual carriers. Release 10 W-CDMA supports all of the above, and dual carriers can be adjacent, non adjacent but within the same band, or even in different bands (e.g. Cellular 850 MHz and PCS 1900 MHz).

In the LTE spec. a resource block is 180Khz, 100 of which make the 20mhz bandwidth, which is not to be confused with the band. With this maximum bandwidth and at 64QAM your antenna can only(!) spit 75mbps at the cell-tower. Thankfully you have two antennae, so you get 150mpbs. Whether you carve this into two 10mhz channels as an aggregate or have one 20mhz channel, you won't get past 150mbps. With Cat5 LTE you will have 4 antennae available, and thus 300mpbs.Reply

Then lets hope we ditch 3G UMTS/WCDMA asap and move on to LTE. The constant switching from LTE to 3G / 2G signals only for voice is seriously killing the battery.

Answering my own question, on the Qualcomm page it seems this new 9x25 will be using the same 28nm process, but with smaller Die Size and lower power usage! Sounds like another candidate for iPhone 5S to me. and that is just a amazing piece of engineering.

The other thing is i have always thought LTE advanced will be more like 5G, as in how we move from 2G to 3G, now that it seems more like a HSDPA to DC-HSDPA thing. The max speed of the purposed 1Gbps will be achieved by aggregate 100Mhz of spectrum . Which gives a efficiency of 200Mbps per 20Mhz spectrum. Compared to Category 4 LTE modems on 20 MHz FDD-LTE see up to 150 Mbps of throughput. We have an 33.3% improvement in bandwidth. Which is still a very good upgrade, and may be we get lower latency number as well, but not anything close to the advertised 1Gbps. I mean which carrier actually own 100Mhz of spectrum? And decided to use it solely for LTE-A?Reply

I suspect that 100mhz blocks are unlikely to show up anywhere outside the lab, possibly excluding rural broadband initiatives. In the bigger cities there isn't any TV spectrum available to be freed up without kicking stations) off the air; so short of either shutting broadcast TV down entirely (or a major restructuring to a distributed transmission setup like phone service) the only places large amounts of TV spectrum are going to be available to be freed are sparsely populated areas in the country. Those areas don't need more bandwidth for phones; but for residential wireless broadband with usage limits comparable to wireline services lots of spectrum would be needed. Combined with cell sizes of up to 100km this could push usable broadband out to everywhere except in the mountains (where LoS issues will also cause major problems for satellite based services).Reply